Ivan and a few others on this site are way more versed in the politics of the USSR during WW2 than I am.
I will attempt a simple answer...?
Arkadi Shvetsov.s
M-82 (A): 1,330 PS normal power & high S/C (1,510 PS combat power & low S/C)
M-82F: 1,350 (1,700) Take-off: 1,700 PS @ 1,140 mm Hg.
M-82FN: 1,470 (1,850) Take-off: 1,850 PS @ 1,200 mm Hg.
ASh-82FN: 1,470 (1,850) Take-off: 1,850 PS @ 1,200 mm Hg.
Hello Corsning,
If that "Ivan" is me, then thanks for the vote of confidence, but it is a bit misplaced. I just read a bit of Russian and Tomo Pauk is much better at it than I am.
I have been collecting data fairly recently on the La-5FN and here is what I have found that is somewhat relevant to this discussion:
The engine was a Shvetsov M-82FN or ASh-82FN. It was the same in the La-5FN and La-7.
From the La-5FN Flight Manual and Construction Manual (pretty much an E&M manual):
Take-Off Power was 1850 HP @ 2500 RPM with 1180 mm Hg Manifold Pressure.
Nominal Power was 1650 HP @ 2400 RPM with 1000 mm Hg Manifold Pressure at critical altitude 1650 Meters in Low Blower.
Nominal Power was 1450 HP @ 2400 RPM with 1000 mm Hg Manifold Pressure at critical altitude 4650 Meters in High Blower.
Supercharger gear change was at 4000 Meters altitude.
As Tomo Pauk pointed out, "Nominal Power" is what their manuals call it. I normally think of it as pretty much equivalent to our "military power" setting.
Their Take-Off / WEP rating was not useable except in low blower and I believe the limit was 5 minutes duration maximum.
As for weight of the aircraft, I believe they tended to vary A LOT depending on the production series and also depending on whether major structural members were Delta wood, Pine, or Light Alloy. The Rechlin Report by Lerche gives an idea of what the major weights were but I believe the numbers are a bit off.
I believe the numbers from "airpages.ru" seem to be reasonable and not in great disagreement with those of the Rechlin Report.
The problem is that the data is mislabeled.
They list 2828 Kg as Empty Weight. This is probably what we would consider "Basic Weight".
They list 3390 Kg as Maximum Take-Off Weight but I believe this is actually the Loaded Weight.
Here is the Weight Breakdown and how I came to this conclusion:
2828 Kg Basic
80 Kg Pilot
52.3 Kg Lubricant for 58 Liters Capacity. (Rechlin flew with 51 Liters weighing 46 Kg.)
333.6 Kg Fuel for 464 Liters (2 x 148 Liter, 1 x 168 Liter from manual)
94 Kg for 400 rounds 20 mm ammunition
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3387.9 Kg which is pretty close to 3390 as listed.
This is only a few Kg over what was listed in the Rechlin Report.
As for maximum level speed, I believe the anything from about 390 MPH to about 403 MPH is reasonable because construction quality varied quite a bit.
As for the altitude at which it was achieved, my BELIEF is that anything in the 20,000 feet / 6000 Meter range is unrealistic.
The engine had a critical altitude of only 4650 Meters. Any greater altitude for aircraft critical altitude would have to be due to ram effect and I can't see that as adding another 1400 to 1500 Meters.
- Ivan.
Minor Correction: In the weight calculation, I used the Oil Capacity from the La-7. The Oil Capacity for the La-5 and La-5FN was 60 Liters, so with the corrected weights, we have:
2828 Kg Basic
80 Kg Pilot
54.1 Kg Lubricant for 60 Liters Capacity. (Rechlin flew with 51 Liters weighing 46 Kg.)
333.6 Kg Fuel for 464 Liters (2 x 148 Liter, 1 x 168 Liter from manual)
94 Kg for 400 rounds 20 mm ammunition
----------
3389.7 Kg which is VERY close to 3390 as listed.
